Retinitis pigmentosa is a group of inherited disorders in which abnormalities of the photoreceptors (rods or cons) or the retinal pigment epithelium of the retina lead to progressive visual loss. Some forms of retinitis pigmentosa are dominant, requiring only one gene from either parent; others are X-linked, requiring only one gene from the mother. In some people, mostly males, an inherited form of hearing loss also develops.
The retinal pigment epithelium provides nutrients and support to the photoreceptor cells of the retina, in particular, inhibitors of oxidative stress and apoptosis. For example, neurotrophins of the retinal pigment epithelium activate the release of anti-inflammatory and anti-oxidative factors.
In retinitis pigmentosa there is chronic death of photoreceptor cells (rods and cones) of the retina. These photoreceptor cells, which are responsible for vision when light is low, gradually degenerate, so that vision becomes poor in the dark. The first symptoms of retinitis pigmentosa often begin in early childhood. Over time, a progressive loss of peripheral vision occurs. In the late stages of the disease, a person has a small area of central vision and a little peripheral vision remaining (tunnel vision). A need exists in the art for methods of treating retinitis pigmentosa.